Radiant reflector



G. J. HENRY.

RADIANT REFLECTOR. APPLICATION FILED MAR. 10, 1920.

1,393,3 3, Patent ed Oct. 11, 1921..

IN VEN TOR A TTORNE YS State of UNITED STATES "PATENT OFFICE.

Specification of Letters Patent.

Patented Oct. 11, 1921.

Ap lication fled [arch 10, 1920. Serial 110. 364,789.

To all wkomitmay concern:

Be it known 'that I, G'aoner: J. HENRY, a citizenof the United States,and a resident of the cit and county of San Francisco, alifornia, haveinvented new and useful Im rovements in Radiant Reflectors, of which the followin is a specification.

My invention has or its object the formingof a reflector for radiantenergy such that a beam reflected on the surface of-the reflector andoriginating at an energy source substantially, at the focus thereof'Wlll be reflected outwardly as a diverging beam from the reflector; asdistinguished from earlier forms wherein'a beam reflected therefromconvertiges, crossing the axis of the curve of the re ector, or-if of aparabolic form, emanates-asa beam whose ra s are parallel with the axisof the paraboloid'.

My invention is particularly adapted to heaters of the radiant type lnwhich the beam of radiant ener 'is directed from the reflecting surface,an when the reflected rays'of such a beam strike an object on theirpath, they are transformed into heat energy thereby heat' the object. I

A further 0 ject of m invention is providing within t e space tween thereflector and the heat unita supplementary reflector of relativelysmaller dimensions, which receives the most direct rays emanating fromthe heat unit andrefleets them to the surface ofthe larger reflectorwhen they; are a ainreflected outward or divergent and c ear of the heatunit. this supplement'ary-reflecting curved sur ace I prevent theconcentration of reflected rays'back upon the surface of-therheat unit,and. which have heretofore been accompanied by the early destructionofthat ortion of the heat unit thus subjected-to this excessiveheating.-

Or, the reflector may be formed at its central portionwith. a cusp, or.su plementary reflecting curved surface where y the said direct energyrays'instead of bein reflected back on the ad acent ortiono the heatunit are directed away rom such path.

With-my invention .the reflector, and especially the central portionthereof, is kept o'ooleathan in types heretofore emplofying the,continuous curved or flat surface 0 the reflector with itsconcavesurface toward the heat unit.

By referring, to the accompanying drawmy invention will be made clear. v

igure l'illustrates my hyperbolic form of reflector having asupplementary reflecting surface of relativelysmaller dimensions at itscentral portion for diverging the direct rays of the heat unit.

' Fig. 2 shows my su plementary form of reflectormounted at t e centerof a minbolic form of reflector and spaced t ere-- from.

Fig. 3 illustrates the path of the radiant energy which has heretoforeresulted in the eerlydestru'ction of heat units due to the reflectedrays from the-center of the reflec'tor.

Fig. 4 shows the manner in which said rays when reflected are divertedfrom the surface of the heat unit.

.4, 5,6, which are received upon the surface of the reflectors 2 and 3.The ray 5 is reflected from the surface of 2 in the di rection of thearrow 8, the angle of-incidence being equal to the angle of reflection.Due to the properties ofthe hyperbola the reflected ray 8 will bedivergent, the heat unit 1 being mounted at one of the focii of the saidhyperbola. The degree of-divergence ofthe ray'8 is dependent upon thedegree of curvature of 2, which again is dependent upon the relativeosition of the focii"1 and 9 (Fig. 5). If t e surface 2 be revolvedaboutthe axis 10,- a hyperboloid (or hyperbjola of revolution) Wlll beformed, and the rays as 8 and 11 from'the entire surface will form;collectively a radiant beam diverging into space as 'it issues from thereflector. These rays will not cross'the axis 10 and therefore arelatively even distribution of the: energy in the space in front of thereflector 2 will be secured .with the least danger. of fire due to theconcentration ofrays where they would cross the axis in other forms.

In Fig. 2 the'well known form of parabola ios is shown, in which rays,as 6, striking the surface of 3 from the energy source 1, will issuefrom the surface of the parabola as indicated by the arrow 12, parallelwith the axis 10.

In the preferred form of radiant heaters these reflectors as '2, 3, arerelatively small; whereas, the area to be covered by the radiant beam isusually of relatively larger di? mensions, and therefore the parallelbeam from the parabolic reflector of Fig. 2 does not cover a sufficientarea, whereas the beam emanating from my hyperbolic reflector, (Fig. 1),may, depending upon the curvature of the hyperbola, have any degree ofdivergence and therefore be made to cover any re uired area.

n Fig. 3 is shown the effect of the rays emanatingfrom the energysource, or heat unit 1, due to their reflection from the relatively flatsurface of the back of the reflector 13, and which are returned'upon theheat unit as at 14, thereby raising the temperature of that portionindicated by the black area 15, to a much higher degree than the balanceof the unit. This results in the early destruction of the heat unit ator about that portion indicated -by the numeral 15. To overcome this Iform the back of the reflector near its center with a cusp, or suplementary reflecting surface, as shown at ig. 4, which surface may bemade integral with, or mounted on, or spaced from the reflector surface16. Such acusp spaced from the reflector 16 is shown by the numeral 17,and it willbe'seen that the beam of energy emanating from the heat unit1 will be received upon the surface of the cusp, and directed asindicated by the arrow 18, thus effectually preventing its return uponand destruction of the heat unit 1, and thedistribution of the radiantenergy on the reflecting surface is much better.

' At 4 (Fig. 1) is shown the further path of such a ray which firstemanates from the heat unit 1, and is then reflected upon the surface19, until it strikes the surface of the hyperbolic reflector 2, as atthe point 20, when it is reflected again, as in the direction '11. Asimilar result is attained with the parabolic reflector 3, Fig. 2, whenprovided with my supplementary reflecting surface whereby the ray '7 'isfirst reflected upon the surface of the cusp 19, impinging upon thereflector 3 at the point 21, and is reflected therefrom as indicated bythe ray 22, thus effectually protecting the heat unit from destruction,and providing a radiant divergent reflected beam from those portions ofthe heat unit, which heretofore were quickly destroyed by the returningenergy from the flat surface of the reflector as at 13, Fig. 3.

The hyperbolic curve, which corresponds with the cross section throughmy preferred formed such that the distance from the point 24 (on theline 9-23) to the point on the'surface of the curve 2, plus the d15-tance.25 '-1 is equalto the distance 24-26 plusthe distance 26--1.

The revolution of the curve 2 about the axis 10 will produce the curveof the surface of the hyperbolic reflector; or, instead of revolvingabout the axis 10 the rc'flector'may be formed of a plane surface bentinto the curve 2. The focus of such a plane surface bent into said curve2 will then be a line instead of a point, and the heat unit may besuitably elongated; or, in practice the heat unit 1 may be somewhatelongated in the direction at right angles to the figures, and thesurface 2 being relatively much larger than the said unit mayadvantageously be retained as a hyperboloid of revolution.

Moreover, in practical work the heat unit 1 is usually of a "materialsize instead of a mathematical point, and may be of any well known form,as for example, triangular in cross section in which case a greaterpercentage of the energy emanating from the said heat unit will bereflected from the surface of the reflector. My invention, however, isdirected to the shape of the reflector and the path of the rays receivedthereon from any heat unit mounted substantially at or about a focalcenter thereto, and not to a specific form of the heat unit itself.

I claim:

1. A reflector for radiant energy com rising a smooth surface ofhyperbolic form, and a heat element located substantially about thefocus of the curve surface in combination with a supplementary reflectorof cusp form located within the first named rehector and adjacent to theheat element.

2. A. reflector for radiant energy comp'ri'sing a smooth surface ofhyperbolic form, and a heat element located substantially about thefocus of the curve surface in combinatlon with a supplementary reflectorof cusp form located within the irst named reflector and adjacent to theheat element, and spaced therefrom to prevent heat conduction betweenthe reflectors.

3 A reflector for radiant energy consisting of a surface of curved formand a heat element located within said curve in combination with asupplementary reflector of cusp form located within the first namedreflector and adjacent to the heat element.

4. A reflector for radiant energy "consisting of a surface of curvedform and a heat element located within said curve in combination with asupplementary reflector or cusp form located within the first namedreflector and adjacent .to the heat element and spaced therefrom toprevent heat conduction between the reflectors.

5. In an electric heater a heat element and a reflector of curved formpositioned to receive radiant energy emanating from said element and t0reflect the same in a divergent beam of substantially constant intensitythroughout the cross section of said beam, in combination with asupplementary reflector of cuspform located within the vfirst namedreflector and adjacent to the heat element.

6. In an electric heater, a heat element ment and reflect same as adiverging beam in combination with a supplementary reflector of cuspform located within the first named reflector and adjacent to the heatele-' ment, and spaced therefrom to prevent heat conduction between thereflectors.

In testimon whereof, I have hereunto set my hand at an Francisco,California.

GEORGE J. HENRY.

